Series stacked ignition system using series diodes in the bases



G. SOHNER 3,167,705

SERIES STACKED IGNITION SYSTEM USING SERIES DIODES IN THE BASES Jan. 26, 1965 Filed Dec. 19, 1961 /NVE'NTOP 611-14"! 67.-

United States Patent 3,167,765 SERIES STACKED IGNITION SYSTEM USIN SERIES DIODES IN THE BASES Gerhard Siihner, Endershach, Kreis Waihlingcn, Germany, assignor to Robert Bosch G.m.b.H., Stuttgart,

Germany 7 Filed Dec. 19, 1961, Ser. No. 160,455

iaims priority, application Germany, Dec. 22, 1960,

B 60,590 3 Claims. (Cl. 323-62) the fact that the transformation ratio of the ignition coil must be chosen ata rather high value in view of the high permissible blocking potentials of the transistor. Even the provision of the two transistors in series connection does not yield better results unless, in accordance with the prior art, rather involved auxiliary circuits are used in such an arrangement.

It is among the objects of this invention to provide for an ignitioncontrol arrangement of the type set forth which safely avoids the above mentioned difliculties.

It is another object of this invention to provide for such an arrangement which is comparatively very simple in its structure and entirely reliable in operation.

With above objects in view the invention includes in an ignition control arrangement for internal combustion engines, in combination, a source of continuous electric energy; control pulse generator means for furnishing control pulses adapted to time the ignition moments; ignition coil means having a primary winding and a secondary winding for'delivering a high voltage ignition pulse in response to an interruption of current flow through said primary winding; atleast two transistor means having their emitter-collector circuits connected in series with each other and in circuit with said source and said primary winding, the base electrodes .of 'said transistor means being in circuit with said control pulse generator means in such a manner that during each of said control pulses said transistor means are conductive so as to pass current from said source to said primary winding, and that during the intervals between said control pulses said transistor means are non-conductive so as to interrupt said current; and at least one rectifier means connected between the base electrodeof one of said transistor means and said control pulse generator in such a manner that the emitterbase current of said one transistor means is enabled to pass through said rectifier means. f i

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is an illustration of the general structure of a control arrangement according to the invention; and

FIG. 2 is a schematic circuit diagram of the illustrated arrangement.

The illustrated ignition control arrangement adapted to cooperate with a four-cylinder four-cycle internal com- The invention itself, however, both bustion engine (not shown) having an ignition distributor switch 10 and interrupter means contained in the distributor housing (or equivalent control pulse generator means) comprises an ignition coil assembly 11 and, control circuit means described further below and including transistors 12 and 13, the whole control arrangement being arranged within a housing 15 attached to the housing of the ignition coil 11 by means of a strap 14.

The ignition coil assembly 11 is equipped with a primary winding 20 made of a small number of turns of rather thick wire :and a secondary winding 21 which is preferably mounted on a common iron core 22. The secondary winding serves to produce a high voltage igni tion pulse every time when the flow of current through the primary winding 26 is interrupted, and is made of rather thin wire in about 200 times as many turns as the primary winding. One end of each of the windings is connected via a' common terminal 23 with electrical ground and with the minus terminal of a source of continuous electric energy, e.g. a six volt battery 24. The other end of the secondary winding 21 is connected via a plug 25 and a cable 26 leading to the distributor 10, or more particularly with the rotary arm 27 thereof which is adapted to be driven through the projecting shaft 28 at a speed equal to one-half of the crank shaft speed of the engine. As the arm 27 passes during its rotation over the individual distributor contacts 29, the ignition pulses are deliveredsequentially to the four spark plugs of the engines, one

of which is illustrated at 30.

The second end of the primary winding 29 is connected with a terminal 32 mounted in the insulating lid 31 of the coil assembly 11, and the terminal 32 is connected by a line 33 with a terminal 34 of the control circuit arrangement 15 described further below.

In this control circuit arrangement two transistors 12 and 13 have their emitter-collector circuits connected in series with each other between the above mentioned terminal 34 and a terminal 35 which latter is connected via a line 36 with the positive terminal of the battery 24. The base electrode of the transistor 12 is connected in accordance with the invention via' a rectifier 40 with a terminal 39 connected via line 39 with the movable interrupter contact 38. The interrupter contact 38 is actuated in conventional manner by a rotary cam member 50 driven in conventional manner by the engine via its shaft 28 so as to periodically move the contact 38 into and out of engagement with the stationary contact 51. The arrangement 28, 38, 50, 51 constitutesfa control pulse generator because it is in circuit with the battery 24. It should be noted however that the control pulses referred to further belowmay also be generated by different means than the above mentioned and illustrated interrupter, e.g. by a four-pole alternating current generator driven in synchronism with the distributor shaft 28 and furnishing four brief control pulses per revolution.

The above mentioned rectifier 40 is arranged in such a manner that theemitter-base current of the transistor 12 is enabled to pass through the rectifier 4t) withou encountering an appreciable resistance.

If desired, and in most cases with additional advantage, a second rectifier 41 is connected. in the same manner between the base electrode of the transistor 13 and the above mentioned terminal 39.

' Between the base electrode of each of the transistors 12 and 13 and the respectively associated rectifiers 40, and 41'protective resistors 42 and 43, respectively, are inserted, while between the base electrodes and the emitters of transistors 12 and 13, respectively, additional resistors 44 and 45, respectively, are provided. In order to assure uniformity of load on the transistors 12 and 13 the emittercollector circuits thereof are shunted by resistors 46 and 47, respectively, having equal resistances.

Patented Jan 26, 1 965 s ea /o5 In operation the above described arrangement functions as follows: As long as or whenever the cam 50 is in a position in which the movable interrupter contact 38 is in engagement with the stationary contact 51 an emitter-base current flows through each of the transistors 12 and 13 and via the rectifiers 40 and 41, the magnitude of this current being limited by the protective resistors 42 and 43, respectively. By these emitter-base currents the transistors 12 and 13 are rendered conductive. Under these conditions a strong current is permitted to flow across the emitter-collector circuits of the transistors 12 and 13 and through the primary winding 26 whereby a strong magnetic field is set up in the iron core 22. However, as soon as the cam 50 lifts the interrupter contact 38 from the contact 51 the emitter-base current controlling the conductivity thereof and passing through the rectifiers 4t), 41, respectively, is interrupted. It should be noted that at this moment the two rectifiers are connected with each other in opposite directions of conductivity so that the two transistors are safely separated or decoupled from each other. Consequently both transistors are rendered non-conductive simultaneously and interrupt the magnetizing current passing through the primary winding 20 whereby a high ignition voltage is induced in the secondary winding.

In order to protect the transistors against overload when the engine is standing still and when under such a condition the contacts 38 and 51 are in mutual engagement, a further protective resistor 69 of about .1 ohm is inserted between a junction point in the emitter connection of the transistor 13 and the line 35 leading to the positive terminal of the battery 24.

It is to be understood that in many cases it is sufficient if only the transistor 12 directly connected with the primary winding 20 is protected by the rectifier 40, while the rectifier 41 is omitted in the connection between the base electrode of transistor 13 and the terminal 39. It can be seen readily that the arrangement of the rectifiers 4t 41 in the base circuit or circuits of the transistor 12 or transistors 12, 13, respectively, results in a remarkably high degree of safe operation of the entire control circuit arrangement 15 because the two transistors are decoupled from each other by the rectifiers at the moment when an ignition pulse is produced and transmitted to the spark p ugs.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of ignition control arrangement for internal combustion engines differing from the types described above.

While the invention has been illustrated and described as embodied in ignition control arrangement for internal combustion engines and comprising a plurality of transistors, it is not intended to be limited to the details shown, since various modifications and tsructural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended'to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In an ignition control arrangement for internal combustion engines, in combination, a source of continuous electric energy; control pulse generator means for furnishing control pulses adapted to time the ignition moments; ignition coil means having a primary winding and a secondary winding for delivering a high voltage ignition pulse in response to an interruption of current flow through said primary winding; at least two transistor means having their emitter-collector circuits connected in series with each other and in circuit with said source and said primary winding, the base electrodes of said transistor means being in circuit with said control pulse generator means in such a manner that during each of said control pulses said transistor means are conductive so as to pass current from said source to said primary winding, and that during the intervals between said control pulses said transistor means are nonconductive so as to interrupt said current; and at least one rectifier means connected between the base electrode of one of said transistor means and said control pulse generator in such a manner that the cmitter-base current of said one transistor means is enabled to pass through said rectifier means.

2. In an ignition control arrangement for internal combustion engines, in combination, a source of continuous electric energy; control pulse generator means for furnishing control pulses adapted to time the ignition moments; ignition coil means having a primary winding and a secondary winding for delivering a high voltage ignition pulse in response to an interruption of current flow through said primary winding; at least two transistor means having their emitter-collector circuits connected in series with each other and in circuit with said source and said primary winding, the base electrodes of said transistor means being in circuit with said control pulse generator means in such a manner that during each of said control pulses said transistor means are conductive so as to pass current from said source to said primary winding, and that during the intervals between said control pulses said transistor means are non-conductive so as to interrupt said current; and at least one rectifier means connected between the base electrode of that one of said transistor means which is closest to said primary winding and said control pulse generator in such a manner that the emitter-base current of said one transistor means is enabled to pass through said rectifier means.

3. In an ignition control arrangement for internal combustion engines, in combination, a source of continuous electric energy; control pulse generator means for furnishing control pulses adapted to time the ignition moments; ignition coil means having a primary winding and a secondary winding for delivering a high voltage ignition pulse in response to an interruption of current flow through said primary winding; at least two transistor means having their emitter-collector circuits connected in series with each other and in circuit with said source and said primary winding, the base electrodes of said transistor meansbeing in circuit with said control pulse generator means in such a manner that during each of said control pulses said transistor means are conductive so as to pass current from said source to said primary winding, and that during the intervals between said control pulses said transistor means are non-conductive so as to interrupt said current; and two rectifier means connected between the base electrodes of said two transistor means, respectively, and said control pulse generator in such a manner that the emitter-base currents of each of said transistor means are enabled to pass through the respective rectifier means.

No references cited.

ARTHUR GAUSS, Primary Examiner, 

1. IN AN IGNITION CONTROL ARRANGEMENT FOR INTERNAL COMBUSNTION ENGINES, IN COMBINATION, A SOURCE OF CONTINUOUS ELECTRIC ENERGY; CONTROL PULSE GENERATOR MEANS FOR FURNISHING CONTROL PULSES ADAPTED TO TIME THE IGNITION MOMENTS; IGNITION COIL MEANS HAVING A PRIMARY WINDING AND A SECONDARY WINDING FOR DELIVERING A HIGH VOLTAGE IGNITION PULSE IN RESPONSE TO AN INTERRUPTION OF CURRENT FLOW THROUGH SAID PRIMARY WINDING; AT LEAST TWO TRANSISTOR MEANS HAVING THEIR EMITTER-COLLECTOR CIRCUITS CONNECTED IN SERIES WITH EACH OTHER AND IN CIRCUIT WITH SAID SOURCE AND SAID PRIMARY WINDING, MTHE BASE ELECTRODES OF SAID TRANSISTOR MEANS BEING IN CIRCUIT WITH SAID CONTROL PULSE GENERATOR MEANS IN SUCH A MANNER THAT DURING EACH OF SAID CONTROL PULSES SAID TRANSISTOR MEANS ARE CONDUCTIVE SO AS TO PASS CURRENT FROM SAID SOURCE TO SAID PRIMARY WINDING, AND THAT DURING THE INTERVALS BETWEEN SAID CONTROL PULSES SAID TRANSISTOR MEANS ARE NONCONDUCTIVE SO AS TO INTERRUPT SAID CURRENT; AND AT LEAST ONE RECTIFIER MEANS CONNECTED BETWEEN THE BASE ELECTRODE OF ONE OF SAID TRANSISTOR MEANS AND SAID CONTROL PULSE GENERATOR IN SUCH A MANNER THAT THE EMITTER-BASE CURRENT OF SAID ONE TRANSISTOR MEANS IS ENABLED TO PASS THROUGH SAID RECTIFIER MEANS. 